My take on the sidewinder primary clutch

[Snowaddict]

I must be lucky because I have 3k km on mine, stock everything including the belt, clutches work great! Every time I go out I warm up the belt almost like I was breaking it in... I have always done that and haven't blown a belt in over 20 yrs lol

Glenn, that's awesome. Have you looked at either of your springs? Is there any paint missing from the coils?

 

[GlennM]

Glenn, that's awesome. Have you looked at either of your springs? Is there a by paint missing from the coils?

Yes, a slight scrape on my prmary which happened during break-in, nothing more since. My secondary rollers were also replaced under warranty. One had a small flat spot. No issues since.

 

[Conedodger]

I would not sweat the gussets missing in the OP pics. I'm sure these are all drawn up in solidworks and as a piece that spins high and if poorly designed grenades ( we know about that right??) I'm sure the designs get optimized using FEA (finite element analysis) to find stress risers, load paths and design sweet spot. Can you tell I'm an aviation Engineer? lol.

That said I bought a 911 cover and glide washers because I believe in the design benefits.

 

[snowbeast]

There is very little movement with the way these are mounted. Far far less then the 4tec doo for sure.

Dan,just so you know,i did some lake runs last sunday,and my first run was with my new 8dn belt that had 130 plus miles on it,so I felt it was broke in correctly,my gps was 113 next run was stock well broken in 8jp 117 gps,so as you stated before,these two belts will produce different top speeds,and the winner speed wise is the stock dusty 8jp,by 4mph GPS verified.

 

[snowbeast]

I hope I don't start breaking belts now that I will say,i have 1500 hard miles on a tuned 265 hp plus winder on stock 8jp belts and all run great,have not had any belt issues to date,hope I don't either.

 

[ryama]

I have 1800 kilometres on my sled . 400 with a 265 tune,original belt and clutch has been great except for the rattle. As far as I'm concearned the drive train is solid. Job well done Yamaha.

 

[stone88]

Be warned the 8DN belt is very hard and can damage your primary.

Sent from my LG-D852 using Tapatalk

I'm seeing this over and over in a lot threads lately the 8dn belt is not HARDER its actually softer and will be 2-300 rpms lower equally broke in which is fine but you will lose 3-4% overdrive on it but if you don't care about that you will be fine just adjust your weights to the belt.

 

[snowbeast]

I'm seeing this over and over in a lot threads lately the 8dn belt is not HARDER its actually softer and will be 2-300 rpms lower equally broke in which is fine but you will lose 3-4% overdrive on it but if you don't care about that you will be fine just adjust your weights to the belt.

I ran both 8dn and my stock 8jp on my 265 hp winder,last weekend up in Sherman area on perry pond,2 miles long,and knowing my rpms were down because of heavy weights I had left in,so that is why they were down,i had a brand new 8dn I had broke in with 130 miles on it,so my first pass was with that belt,belt was warm from the 20 mile drive to the pond,so I set out to check pond for bad spots before I ripped it acrossed,it was fairly flat,with small bumps from heavy rain on the heavy snow it had before those days of the rain. Ok so ran it down 113 gps rpms 8000 should be 9100 EVO 4 tune,ok just changed belt to 8jp took it for a spin to heat the belt some,ran it same path 117 gps rpms still 8000 did not notice much rpm change between the two,but the mph drop from the longer 8dn,these are my results on that day.

 

[NOS-PRO]

Terry did you machine your Primary?

Yes, I am machined. Been machining Yamaha clutches for overdrive for years. If I would have known prior to my machining that the inner sheave diameter was smaller, I wouldn't have touched it.

In my mockup(pic above) the primary is clamped closed fully...belt is down about 3/16" on inner sheave.

Only way its coming out is if it stretches/blows.

Dan, this is mocked up at a standstill and I did the same mock-up thing. My belt was about .040" from being flush with the top of the primary when I had a brand new belt and after I did the machining. Never thought it would climb over either. But under load, you can see in my video of clutching how the belt doesn't come at the primary straight on from the secondary, but more at a curve.....especially if you hit the brakes, rev limiter or bump. I will be hooking up my camera more showing more videos.

This video was just be-bopping down the trail....max speed was 50-60 mph.

This video was a short burst down the trail where max speed was 85mph

When my belt climbed over the primary sheave at 130gps, it was cut clean like a knife or grinder cut it. Also, the marks on the engine tell the tale. The inner sheave on mine shows clean all the way to the top...so my thinking is that my primary (being machined) carried the belt to the top edge, the top edge of the belt went over twisting the belt leaving the black marks on the moveable sheave and top edge of the inner sheave. After that, the belt went over pinching it between the engine and inner sheave where the sheave cut it.

 

[NOS-PRO]

I think the real issue is the extra power.. not just 10 or 25 hp, its the 265 HP plus that will be the problem in the future. Clutches being raced and pounded are going to let go.. if your going to run gobs of 265 plus HP you should go to Billet Clutches to be safe or you are asking for it. Tossing on a Viper or Apex clutch is not the answer. I feel tat would be a foolish bandage to the real issue. PURE POWER. The damn belt cant stay together, do you actually think the clutches will?

And Sled is right....this is the most power "I" have ever had in a sled, I do race mine and do a lot of testing that really puts stress on parts...especially the clutch. Looking at billet aftermarket clutches for my summer asphalt racing, but going to try the Viper clutch for trail and winter time. Again, I run my sled far beyond what it is geared at. The turbo RX1's never had issues with the primary clutch so this is why I am going to try the previous style Yamaha clutch until I can get an aftermarket clutch my way. Belts? guess there has to be a limit somewhere on how much power they can take.

(Time to drop in a turbo R1 rocket engine, run a heavy duty chain straight to the drive axle with a manual clutch. No belts, no exposed clutches and no chaincase)

 

[SideHogger]

Anyone know if Knappattack tried a power bloc clutch yet?

 

[Soupy]

(Time to drop in a turbo R1 rocket engine, run a heavy duty chain straight to the drive axle with a manual clutch. No belts, no exposed clutches and no chaincase)

Love it

 

[LouTurbo]

Nospro, How do you ride with one hand under the hood holding the camera, just kidding.
the videos present great insight, being a seasonal rider its an eye opener to me.

 

[ROCKERDAN]

Yes, I am machined. Been machining Yamaha clutches for overdrive for years. If I would have known prior to my machining that the inner sheave diameter was smaller, I wouldn't have touched it.



Dan, this is mocked up at a standstill and I did the same mock-up thing. My belt was about .040" from being flush with the top of the primary when I had a brand new belt and after I did the machining. Never thought it would climb over either. But under load, you can see in my video of clutching how the belt doesn't come at the primary straight on from the secondary, but more at a curve.....especially if you hit the brakes, rev limiter or bump. I will be hooking up my camera more showing more videos.

This video was just be-bopping down the trail....max speed was 50-60 mph.

This video was a short burst down the trail where max speed was 85mph

When my belt climbed over the primary sheave at 130gps, it was cut clean like a knife or grinder cut it. Also, the marks on the engine tell the tale. The inner sheave on mine shows clean all the way to the top...so my thinking is that my primary (being machined) carried the belt to the top edge, the top edge of the belt went over twisting the belt leaving the black marks on the moveable sheave and top edge of the inner sheave. After that, the belt went over pinching it between the engine and inner sheave where the sheave cut it.

View attachment 136833 View attachment 136834

Terry,

First off excellent video. I think this type of video footage can tell us a TON about what is going on with our belts and belt life. I find the one where you are trail riding so interesting, and the lack of tension and slap the belt seems to go thru.

Is there any way you can attach the cam so it is straight on? So its directly looking at the belt from topside somehow, just to see how straight it all runs under load?

As for the belt coming over the top.....I 100% agree with you, that looks like what happened, However I feel that since the belt is a certain length, and in the mockup the belt is BOTTOMED OUT in secondary, so it cannot go any higher in primary, Therefor it could not climb over top AND remain in one piece. Only way that belt can come out and overtop would be to massively stretch, since the secondary is holding it there bottomed out.

So I believe when your belt came out, over top and did what it did....It MUST have let go enough or somehow stretched that much to allow it to climb out.

I would love to see more video like this, I think its a telltale sign of whats actually happening under there. I hate to say it as Ive always loved the torsional design. But it sure seems that the compression setup is a more consistent setup when tuning, I know on the 1200 4tec many of us went from torsional back to compression with great success. Its easy on the DOO as the OD of their springs are same. I believe that is nearly impossible with this Helix YAM has, as its such a short pocket, and there are no compression springs that are even close to this size and fitment.

Has anyone tried a diff secondary? It makes me wonder if this type of roller with torsional can keep up , after watching your video.

Dan

 

[KnappAttack]

I ran both 8dn and my stock 8jp on my 265 hp winder,last weekend up in Sherman area on perry pond,2 miles long,and knowing my rpms were down because of heavy weights I had left in,so that is why they were down,i had a brand new 8dn I had broke in with 130 miles on it,so my first pass was with that belt,belt was warm from the 20 mile drive to the pond,so I set out to check pond for bad spots before I ripped it acrossed,it was fairly flat,with small bumps from heavy rain on the heavy snow it had before those days of the rain. Ok so ran it down 113 gps rpms 8000 should be 9100 EVO 4 tune,ok just changed belt to 8jp took it for a spin to heat the belt some,ran it same path 117 gps rpms still 8000 did not notice much rpm change between the two,but the mph drop from the longer 8dn,these are my results on that day.

Pete,
Here's the deal, You were not at a high enough speed to run either belt of of gear there to have any effect of the 8DN being longer and effecting speed that way at all.

Looks like the 8JP is just the better performing belt in this case with that clutch setup that day.

The turbo RX1's never had issues with the primary clutch so this is why I am going to try the previous style Yamaha clutch until I can get an aftermarket clutch my way. Belts? guess there has to be a limit somewhere on how much power they can take.

RX-1 came with geared down & cushioned clutch output shaft too. Big difference as to how hard on clutches and belts that was. Not the clutch itself.

Three cylinder power pulses from the four-stroke hammers them harder plain and simple. Doo's known that on the 1200 for years.

Anyone know if Knappattack tried a power bloc clutch yet?

Not yet. I'm having zero problems in over 1500 miles now on Yamaha clutch, rollers fine, original belt. Its noisy just like the previous 3 cylinder vectors and nytros before it were.

Heading out today to test new tune versions and clutching stuff again. If I have time I may give it a go.

My only concern is my old turbo 1200 Doo just blew a PB80 spring cup last week! Doesn't make one want to put it on really bad.